Endovascular procedures are being used more and more frequently to treat various cardiac and vascular surgical problems. Blocked arteries can be treated with angioplasty, endarterectomy, and/or stenting, using minimally invasive endovascular approaches. Aneurysms can be repaired by endovascular techniques. Another use for endovascular surgery is the treatment of cardiac valvular disease. Valvuloplasties are already being done endovascularly and percutaneous valve replacement will surely follow, as it has already been tested in Europe. A major problem which is common to all these endovascular manipulations is that plaque found in the diseased vessels and valves can be dislodged and result in embolization. A major drawback to endovascular treatment of cardiac valves and arteries in the heart or thoracic aorta is that the dislodged debris can embolize into the carotid vessels resulting in catastrophic consequences such as stroke or even death. Attempts have been made to protect the cerebral vasculature with filters and other devices, but the inadequacy of the present art is obvious in the fact that these devices are rarely used. The plethora of pending patent applications for such protection devices suggests both the inadequacy of the present art and the need for improved devices.
The majority of devices described are filters. The problems with filters include difficulty in placement and retrieval as well as the possibility that a filter will fill abruptly causing blockage of the artery prior to removal of the filter. Cerebral protection requires placement of filters in the carotid arteries, which has the additional drawback of manipulation of the carotid vessels during filter placement while the cerebral vasculature is still unprotected. The risk of stroke for a carotid arteriogram done by cannulation of the carotid artery is 1% compared to an arteriogram done from injection into the aorta without selective cannulation which carries minimal risk. The risk of cannulating a carotid artery, navigating a catheter containing a filter into position, and deploying the filter would likely carry an even higher stroke risk. Patients requiring cardiac or aortic arch procedures are high risk candidates for having carotid disease. The chance of causing a stroke by the placement of the protective device into both carotid arteries makes the risk of using these devices prohibitive. The time and skill necessary to selectively cannulate both carotid arteries for filter placement has also contributed to the decision not to use them despite the stroke risk of unprotected cardiac and aortic arch procedures.